Using nuclear magnetic resonance (NMR) technology, this paper proposes a new pore structure parameter called 'effective mobile fluid saturation', which can account for two factors that influence ...mobile fluids in pores: the stiction of hydrophilic particulates on the surfaces of pores and the constraints of tiny throats. The new parameter quantifies the effective content of the mobile fluids and compensates for the deficiencies using conventional parameters like 'mobile fluid saturation'. Pore-throat connectivity is crucial for effective mobile fluid saturation, which reaches its highest point when the sorting coefficient is in the range of 1.5-2.0. Recognition of the pore-throat configuration is crucial in assessing the effectiveness of mobile fluids in tight sandstone reservoirs. Factors that influence the effectiveness of mobile fluids in three types of pore structures are discussed from a diagenetic perspective, including the development of microfractures and secondary pores, recrystallisation, clay mineral precipitation, and other micropore structure characteristics.
Photoperiod-sensitive genic male sterile (PSGMS) rice has a number of desirable characteristics for hybrid rice production. In this study we made use of a published rice genetic linkage map to ...determine the locations of PSGMS genes and we have characterized the effects of these genes on sterility by using molecular markers. A two-step approach was designed for mapping the genes: (i) identifying possible PSGMS gene-containing chromosome regions with bulked DNA from extreme fertile and extreme sterile plants of a very large F2 population and (ii) determining the map locations of the genes in extreme sterile individuals. We show that this mapping method is much more cost effective and statistically efficient than using a random sample of an F2 population. We identified two chromosomal regions each containing a PSGMS locus, one designated pms1 on chromosome 7 and one designated pms2 on chromosome 3. The existence of these two loci was confirmed by a large sample assay and with data on ratooning progenies of the F2 plants. A marker-based analysis shows that the effect of pms1 is 2-3 times larger than that of pms2 and that dominance is almost complete at both loci. Implications in the breeding of PSGMS rice lines are discussed
Multiferroic tunneling junction based four-state non-volatile memories are very promising for future memory industry since this kind of memories hold the advantages of not only the higher density by ...scaling down memory cell but also the function of magnetically written and electrically reading. In this work, we demonstrate a success of this four-state memory in a material system of NiFe/BaTiO3/La0.7Sr0.3MnO3 with improved memory characteristics such as lower switching field and larger tunneling magnetoresistance (TMR). Ferroelectric switching induced resistive change memory with OFF/ON ratio of 16 and 0.3% TMR effect have been achieved in this multiferroic tunneling structure.
This study aimed to investigate the effect of icariin (ICA) on thin endometrium in a rat model. To this end, 6- to 8-week-old female Sprague Dawley rats (105) were randomly divided into 7 groups: ...untreated, vehicle-treated (lavage with NaCl), high-dose ICA (lavage with ICA at 200 mg∙kg
∙day
), medium-dose ICA (lavage ICA at 100 mg∙kg
∙day
), low-dose ICA (lavage with ICA at 50 mg∙kg
∙day
), sham model (injected with NaCl at uterus horn), and sample group. To induce thin endometrium, rats of all groups (except sham-model) were injected with 95% ethanol via the uterine horn. Each group underwent its respective treatment for 3 estrous cycles, after which 5 rats from each group were sacrificed, and endometrial thickness was measured. The expression of CD31, factor VIII, vascular endothelial growth factor (VEGF), cytokeratin (CK), and vimentin were detected via immunohistochemistry. The results showed that CD31, factor VIII, and VEGF were primarily expressed in the cytoplasm of endometrial and vascular epithelial cells. No difference in the expression of these factors was detected between the ICA lavage groups and the untreated groups. However, high dose ICA-treated group exhibited significantly higher expression of CD31, factor VIII, and VEGF compared to that in the low dose and vehicle-treated groups. CK and vimentin in the endometrial tissue were significantly higher in the untreated and treatment groups compared to the vehicle-treated group. This study demonstrated that ICA increases thickness of the endometrium, and it may modulate expression of VEGF, CD31, and factor VIII.
A novel PtPd/C nanocrystals catalyst with truncated‐octahedral structure has been successfully prepared by ethylene glycol reduction to induce anisotropic growth in an isotropic medium by adding a ...small amount of Fe3+ species. Its structure, composition, and morphology are characterized by X‐ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy‐energy dispersive spectroscopy elemental maps, respectively. The electrochemical measurements demonstrate that the highly dispersed and uniform PtPd/C nanocrystals have excellent poisoning tolerance, significantly higher electrocatalytic activity and durability for the methanol oxidation, as compared to solid solution PtPd/C and Pt/C catalysts. This may be ascribed to the stepped atoms and dangling bonds, which served as active sites for breaking chemical bonds during oxidation–reduction reaction; the high density of preferred crystal planes of (111) facets greatly enhanced the oxidation of poisonous residues during reaction.
The results of photometry of three gamma-ray-loud quasars, PKS 1510−089, 3C 279 and OJ248, during 2001 in the B, V and R bands and implications for the supermassive black hole (SMBH) model in these ...objects are presented. The results show that the three quasars had significant, but irregular, rapid outbursts with a typical time-scale of about 40–60 min and a typical amplitude of about Δm≃0.60–1.26 mag during the observations. For 3C 279 and OJ248 the upper limits of the masses of SMBHs are estimated from the observed minimum optical variability time-scale, and the lower limits are also estimated by a method proposed by Dermer & Gehrels. The masses derived from both methods are reasonable. For PKS 1510−089 a new brightness minima was also observed. Analysing the observations from 1999 to 2001, three minima were observed. Although their light curves are poorly sampled, it is intriguing to note that these minimum at intervals of about 43 min seem to indicate the possibility of a periodic phenomenon. So a hypothesis is proposed to interpret the phenomenon, suggesting that there is a binary black hole system at the centre. The parameters of the system are estimated by a very simple method. The periodicity is about 336±14 d in the observed frame; the masses of the primary and secondary black holes are 108.0 and 106.2 M⊙, respectively; the distance between two black holes is 1015.81 cm (378Rg of the primary black hole), and the lifetime of the system is 106.0 yr. These results seem to indicate that PKS 1510−089 is another possible candidate binary black hole system. It should be monitored in future to obtain more data for further analysis to test the hypothesis.
In 2008, the blazar Markarian 421 entered a very active phase and was one of the brightest sources in the sky at TeV energies, showing frequent flaring episodes. Using the data of ARGO-YBJ, a full ...coverage air shower detector located at Yangbajing (4300 m a.s.l., Tibet), we monitored the source at gamma-ray energies E>0.3 TeV during the whole year. The observed flux was variable, with the strongest flares in March and June, in correlation with X-ray enhanced activity. While during specific episodes the TeV flux could be several times larger than the Crab Nebula one, the average emission from day 41 to 180 was almost twice the Crab level, with an integral flux of (3.6 {+-} 0.6) x 10{sup -11} photons cm{sup -2} s{sup -1} for energies E>1 TeV, and decreased afterward. This Letter concentrates on the flares that occurred in the first half of June. This period has been deeply studied from optical to 100 MeV gamma rays, and partially up to TeV energies, since the moonlight hampered the Cherenkov telescope observations during the most intense part of the emission. Our data complete these observations, with the detection of a signal with a statistical significance of 3.8 standard deviations on June 11-13, corresponding to a gamma-ray flux about 6 times larger than the Crab one above 1 TeV. The reconstructed differential spectrum, corrected for the intergalactic absorption, can be represented by a power law with an index {alpha} = -2.1{sup +0.7} {sub -0.5} extending up to several TeV. The spectrum slope is fully consistent with previous observations reporting a correlation between the flux and the spectral index, suggesting that this property is maintained in different epochs and characterizes the source emission processes.
Metallurgical slag, quartz sand and coal fly ash were used as the raw materials for preparation of glass-ceramics according to their compositions and characteristics. Under different mole ratios of ...(CaO+MgO)/SiO
2
, the crystallisation mechanism, microstructure and main mechanical properties of glass-ceramics were systematically investigated through differential thermal analysis, X-ray diffraction, scanning electron microscopy, mechanical and chemical properties test. The results indicate that MgO plays the same role of CaO. The crystallisation activation energy E
a
and crystallisation temperature T
p
decrease as the increase in (CaO+MgO)/SiO
2
ratio. It is found that when (CaO+MgO)/SiO
2
ratio is 0·64 and sintering lasts for 1 h at 996°C, main phase of diopside can be obtained with the best mechanical properties and chemical durability, such as bending strength 110 MPa, microhardness 6·5 GPa, mass loss rate of 0·25 and 0·1% as acid resistance and alkali resistance respectively.
Genomics provides an unprecedented opportunity to probe in minute detail into the genomes of the world's most deadly pathogenic bacteria- Yersinia pestis. Here we report the complete genome sequence ...of Y. pestis strain 91001, a human-avirulent strain isolated from the rodent Brandt's vole-Microtus brandti. The genome of strain 91001 consists of one chromosome and four plasmids (pPCP1, pCD1, pMT1 and pCRY). The 9609-bp pPCP1 plasmid of strain 91001 is almost identical to the counterparts from reference strains (CO92 and KIM). There are 98 genes in the 70,159-bp range of plasmid pCD1. The 106,642-bp plasmid pMT1 has slightly different architecture compared with the reference ones. pCRY is a novel plasmid discovered in this work. It is 21,742 bp long and harbors a cryptic type IV secretory system. The chromosome of 91001 is 4,595,065 bp in length. Among the 4037 predicted genes, 141 are possible pseudo-genes. Due to the rearrangements mediated by insertion elements, the structure of the 91001 chromosome shows dramatic differences compared with CO92 and KIM. Based on the analysis of plasmids and chromosome architectures, pseudogene distribution, nitrate reduction negative mechanism and gene comparison, we conclude that strain 91001 and other strains isolated from M. brandti might have evolved from ancestral Y. pestis in a different lineage. The large genome fragment deletions in the 91001 chromosome and some pseudogenes may contribute to its unique nonpathogenicity to humans and host-specificity.
Aims.The source AC Cnc is a nova-like cataclysmic variable containing a white-dwarf primary with a mass of $0.76\,M_{\odot}$ and a K2-type secondary with a mass of $0.77\,M_{\odot}$. We intend to ...study its period changes and search for evidence of magnetic braking and unseen third body. Methods.The period changes were investigated based on the analysis of the O-C curve, which is formed by one new eclipse time together with the others compiled from the literature. Results.A cyclic change with a period of 16.2 yr was found to be superimposed on a long-term period decrease at a rate of $\dot{P}=-1.24(\pm0.44)\times{10^{-8}}$ days/year. Conclusions.It is shown that the mechanism of magnetic activity-driven changes in the quadrupole momentum of the secondary star (Applegate's mechanism) does not explain it easily. This period oscillation was plausibly interpreted by a light-travel time effect caused by the presence of a cool M-type dwarf companion ($M_3>0.097\,M_{\odot}$) in a long orbit (16.2 yr) around the binary. Since the masses of both components are nearly the same, the mass transfer from the lobe-filling secondary to the primary is not efficient to cause the continuous period decrease. It may be strong evidence of an enhanced magnetic stellar wind from the K2-type component. If the Alfén radius of the cool secondary is the same as that of the Sun (i.e., RA = 15 $R_{\odot}$), the mass-loss rate should be $\dot{M_2}=-1.65\times{10^{-10}}~M_{\odot}$/year. By using the enhanced mass loss proposed by Tout & Eggleton (1988), the mass-loss rate should be $\dot{M_2}=-1.18\times{10^{-9}}~M_{\odot}$/year. In this case, the Alfén radius is determined to be RA = 5.2 $R_{\odot}$. However, the long-term decrease of the period may be only a part of a long-period (>100 yr) oscillation caused by the presence of an additional body. To check the conclusions, new precise times of light minimum will be required.
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